A Kauffman Audio Appliances Aurora overdrive just landed on my bench. I've finished the trace and it's a Timmy with a few parts changed - mostly to the detriment of what makes the Timmy sound great, IMO.
Quick rundown of core differences:
- JRC4558 opamp instead of 4559
- Input resistor changed from 510K to 470K
- Cap to vbias in feedback loop of first stage changed from 39nF to 33nF
- Bass Cut control removed
- Diode switches and associated diodes removed, just has the four clipping diodes, arranged the same as Timmy
- Hi Cut control changed to 100K linear - this is almost unusable to my ears, with the good range only the upper 25% of the rotation
- Volume control changed to 500K audio - this makes the output very low and muddy at any setting other than 90%+
- Power supply capacitor changed from 47uF to 10uF
Don't let the slick video fool you. Inside is the typical sloppy perfboard with spaghetti wire mess and electrical tape we've come to expect from bootweekers who try to cash in on the madness with little knowledge of how to build quality products. Not surprised this guy's business didn't last long. Can't tell whether the footswitch is going bad, or maybe it just needs to be re-soldered, because it looks like some wires are barely attached.